python字典

字典是以 key、 value 的形式创建的。

dict1 = {"name":"xia", "age":"18"}
print(dict1)

#通过key来获取value
print(dict1["name"])
print(dict1["age"])

输出：
{'name': 'xia', 'age': '18'}
xia
18

dict1 = {"name":"xia", "age":"18"}

#从字典中删除数据
dict1.pop("age")
print(dict1)

输出：
{'name': 'xia'}

字典推导式：

{key: value for (key, value)in iterable}

#用字典推导式创建字典
dict1 = {x:x*2 for x in range(5)}
print(dict1)

#两个list创建字段
keys = ['name', 'age', 'city']
values = ['Lemon', 18, 'cs']
dict2 = {k:v for (k,v) in zip(keys,values)}
print(dict2)

输出：
{0: 0, 1: 2, 2: 4, 3: 6, 4: 8}
{'name': 'Lemon', 'age': 18, 'city': 'cs'}

#遍历嵌套字典
dict1 = {1: {'name': 'Lemon', 'age': '18', 'city': 'cs'}, 2: {'name': 'Lemon_zs', 'age': '26', 'city': 'changsha'}}
for main_id, main_info in dict1.items():
    print("main_id:", main_id)
    print("main_info:", main_info)
    for key in main_info:
        print(key + ":", main_info[key])

输出：
main_id: 1
main_info: {'name': 'Lemon', 'age': '18', 'city': 'cs'}
name: Lemon
age: 18
city: cs
main_id: 2
main_info: {'name': 'Lemon_zs', 'age': '26', 'city': 'changsha'}
name: Lemon_zs
age: 26
city: changsha